Usually, traditional bulbs are incandescent light bulbs with low illumination and low energy efficiency. After incandescent light bulbs, fluorescent light bulbs with higher illumination and energy efficiency occurred, but fluorescent light bulbs are not environmental-friendly enough due to the use of fluorescent powder. Therefore, LED bulbs now have come into use after the environmental-friendly and energy-saving LED fight came out. However, structures and manufacturing process of existing LED bulbs are very complicated. For example, the LED bulb and its manufacturing process disclosed in Chinese Patent CN101509616A comprises a lamp cap, a drive circuit component, a light source holder, a LED light source, and a glass bulb shell; the end of the glass bulb shell is fixedly connected with the lamp cap, the LED light source is fixed on the light source holder, the end of the glass bulb shell is sealed on the end of the light source holder and the LED light source and the light source holder are encompassed within the bulb lumen, the drive circuit components is located in the lamp cap and electrically connected with the lamp cap and LED light source through wires. Although this structure is relatively simple and easy to produce, such a LED bulb cannot achieve the effect of all-directional or three-dimensional glowing because the LED light source in the LED bulb are fixed on the light source holder and has the limitation that the light comes from only one side. To achieve the effect of all-directional or three-dimensional glowing, multiple LED light sources toward different directions usually need to be placed. This will raise the cost and it is difficult to assemble. In particular, cooling will become a problem if many LED light sources are placed in an enclosed bulb.
In addition, the technology of LED encapsulation is very important for the application of LED light source. In the prior art, various LED encapsulation methods include lamp LED encapsulation, Chip-on-Board LED encapsulation, Surface Mount Device LED encapsulation, System-in-Package LED encapsulation, etc. Different methods for LED encapsulation will use different encapsulation substrates.
Among the above, Chip-on-Board LED encapsulation is a popular way of LED encapsulation. Traditionally, the substrate for Chip-on-Board LED encapsulation is made of a circuit board or a single material such as metal, PVC, PMMA, or plastic, etc., and often has the shape of a planar rectangular, a planar circle or a planar strip, etc.
However, existing Chip-on-Board LED encapsulation emits planar light after LED chips are mounted on the substrate and sealed with fluorescent adhesive. Because of the flaw of the design, it is often not uniformly glowing around the illuminant. In addition, when the substrate is made of transparent materials, although the glowing is in 360 degrees, cooling problem often occurs because transparent materials usually have a low coefficient of heat transfer; and when the substrate is made of light-proof materials, such as metal, even if the cooling problem may be ignored, the bulb still cannot glow in all directions because there is no light on the side placing the LED chip.
To sum up, the substrate and bulb for existing Chip-on-Board LED encapsulation face the problem of non-uniform glowing angles, which result in an incompetence of multi-angled and multi-layered glowing. In addition, the substrate and bulb also face the problem of cooling, which influences glowing efficiency.